Expired U.S. Pat. No. 4,093,411 (the '411 patent), owned by the same sole inventor as the present sole inventor and incorporated herein by reference, describes an apparatus for in-place formation of foamed polymeric materials and application of those materials to horizontal, vertical, or inclined surfaces including, but not limited to, structural roofs and walls. As the self-propelled '411 patent apparatus moves along a working surface, it dispenses a strip of foamed polymeric material and, if necessary for a particular application, a strip of friction-reducing material and/or a sheet of protective coating. In a series of iterations the apparatus applies a number of strips sufficient to cover the working surface. The beveled, overlapping strip edges join to form a continuous surface that may be, if desired, covered with a protective coating that is dispensed by the apparatus simultaneously with the dispensing of the foamed polymeric material.
The '411 patent apparatus requires uneconomical manned guidance during each iteration to assure straight-line movement and accurate stopping. It also requires uneconomical and laborious manned relocation after each iteration. When a strip is laid, for example from a roof eve to the roof peak, the '411 patent apparatus must be manually and precisely stopped at the peak and then manually and precisely moved the full length of the strip back to the eve to be ready for laying of the next strip from eve to peak.
The present invention improves upon the '411 patent apparatus by eliminating much of its uneconomical labor requirements. Whereas the '411 patent apparatus has a single frame comprising its transport mechanism, the foam mold, and the dispensing means, the present invention incorporates two frames. A bottom frame comprises the transport mechanism and the foam mold, and a top frame comprises the dispensing means. Because the top frame rotates 180 degrees relative to the bottom frame, the present invention apparatus can apply strips of foamed polymeric material to a working surface while moving forward or backward.
The present invention apparatus also improves over the '411 patent apparatus with the additional capability of computer-controlled motion. The new guidance system enables iterations of precise, repeatable distance with minimum human intervention. Another improvement is the addition of an optional means of dispensing adhesive.